Insecticidal compositions comprising denzyl or tetrahydrofurfuryl ester of mucochloric acid



Patented Apr. 28, 1953 .1 3

INSEQ'EICIDAL GOMPOSITIONS COMPRIS- ING HENZYL R TETRAHYDROFURFURYLESTER OF MUCOCHLORIC ACID Horace D. Brown, Plainfield, N. J assignor to.Merck & 00., Inc., Rahway, N. J., a corporation of New Jersey NoDrawing. Application April 17, 1951, Serial No. 221,540

6 Claims. 1

This invention relates to novel insecticidal preparations, and moreparticularly to such compositions containing the benzyl ortetrahydrofurfuryl esters of mucochloric acid.

This application is a continuation-in-part of my copending applicationSerial No. 159,865, filed May 3, 1950, now abandoned (Qase No. 2871).

It is an object of this invention to provide new compositions which areuseful as insecticides for the treatment of plants, grains, organicmater stiles and the like to protect these materials against the ravagesof insects. A further object of this invention is to provide newinsectic dal compositions which can be prepared from relativelyinexpensive and readily available materials. Other objects of thisinvention will be apparent from the detailed description hereinafterprovided.

In accordance with my invention, I have found that the benzyl andtetrahydrofurfuryl esters of mucochloric acid incorporated with suitablecarriers are particularly valuable for insecticidal purposes.Mucochloric acid or a,/3-dichloro-,o-formyl acrylic acid which isrepresented by the following formula:

o=c-o=0-(10H i t1 i1 is prepared by the oxidative chlorination offurfural or Z-furoic acid.

I have found that the benzyl and tetrahydrofuriuryl esters ofmucochloric acid are particularly valuable as insecticides since thesecompounds are highly toxic to insects but relatively non-toxic towarm-blooded animals. While other esters of inuccchloric acid are alsotoxic to insects, the benzyl and tetrahydrofurfuryl esters areoutstanding in that they appear to be more toxic and therefore moreeffective at lower concentrations. Further, in contrast to the loweraliphatic esters, such as the methyl or ethyl mucochloric acid esterswhich are lacrimators and sternutators, the benzyl andtetrahydrofurfuryl esters do not possess these undesirable properties.

The benzyl and tetrahydrofurfuryl esters of mucochloric acid are readilyprepared in accordance with methods known in the art. For example, byheating mucochloric acid with an excess of benzyl or tetrahydrofurfurylalcohol in the presence of a small amount of an acid catalyst such ashydrochloric or sulfuric acid. The corresponding benzyl ortetrahydrofurfuryl ester is formed. The ester thus formed is recoveredfrom the reaction mixture by extraction with a suitable solvent such asether. After evaporation of the solvent, the benzyl ortetrahydrofurfuryl ester can be recovered by fractional distillation ofthe resulting residue. Alternatively, the esters are also prepared byheating required amounts of the acid and alcohol in the presence of anacid catalyst such as toluene sulfuric acid and an inert diluent such ascarbon tetrachloride and the carbon tetrachloride-water azeotroperemoved by distillation. The ester is then recovered from the resultingreaction mixture by the procedure indicated above.

Thebenzyl and tetrahydrofurfuryl esters of mucochloric acid either aloneor in combination with other insecticides and/or fungicidal agents of asuitable carrier thereof may be applied to plants and the like byspraying, dusting, pouring dipping, etc. in the form of solutions,suspensions, powders, and the like containing the most desirable activeprinciples in optimum concentrations for the particular purpose at hand.

Thus, these esters may be incorporated with other insecticides and/orfungicidally active compounds such as pyrethrum, derris resins,rotenone, DDT, hexachlorocyclohexane, nicotine, lime sulfur, Bordeauxmixture, sulfur, fiuosilicates, arsenates, copper salts, lead salts,thiccyano esters, and the like. The exact composi-- tion of the finalinsecticide will of course depend upon the particular application forwhich it is intended. In addition, various wetting and/or spreadingagents such as sulionated oils, salts of higher alcohol sulfates,glycerol esters, sulfonated aromatic and aliphatic hydrocarbons andsalts thereof, sulfonated phenols, and the like may be added inaccordance with the usual practice of the art.

The benzyl and tetrahydrofurfuryl esters of mucochloric acid can be usedin suitable solvents, or mixtures of solvents at optimum concentrationswith respect'to the intended purpose for which it is to be used.Suitable solvents for this purpose include alcohols, esters, petroleumfractions, ketones and the like.

Further, they can be suspended in suitable vehicles or a combination ofvehicles in accordance with the accepted practice in the art. Forexample, they can be suspended in aqueous mediums which may also containvarious wetting or spreading agents and/or other insecticidal orfungicidal compounds.

Alternatively, these esters can also be used in the form of dustingpowders wherein the esters are mixed with or adsorbed on finely dividedcarriers such as volcanic ash, kieselguhr, carbon,

bentonite, fullers earth, nut shell flours, talc and the like.

In general, these active esters may be formulated in a wide variety ofcarriers containing various adjuvants which may be best suited for thecontrol of the particular pest, depending in part upon the habits andnature of these pests. Thus, compositions are prepared with the activeagents in a suitable state of composition, subdivision and associationwhich will be most effective for the particular insecticidal orfungicidal purpose at hand.

The benzyl and tetrahydrofurfuryl esters of mucochloric acid areparticularly valuable for protecting woolen textiles against the ravagesof such textile pests as the black carpet beetle or the webbing clothesmoth. These esters can be applied to such woolen materials by any of thevarious methods well-known in the art for achieving a uniform dispersionof the agent on EXADIPLE 1 The following method was utilized to preparethe benzyl and tetrahydrofurfuryl esters of mucochloric acid:

A solution of mucochloric acid in an excess of benzyl ortetrahydrofurfuryl alcohol containing a small amount of sulfuric acidwas heated under reflux for about 24 hours. After cooling, the resultingsolvent mixture was diluted with water, and extracted with ether toobtain an ether solution of the ester. This ether solution was thenevaporated to obtain a residue consisting of the desired ester ofcucochloric acid. If desired, this ester may be further purified byfractional distillation under diminished pressure.

The benzyl ester of mucochloric ester prepared in accordance with theforegoing process was found to be an oil having a boiling point of about160 to 165 C. at 1 mm. Anal. calc. C, 50.99, H, 3.11, Cl, 27.37. Found:C, 52.01, H, 3.19, Cl, 26.31.

The tetrahydrofurfuryl ester also prepared in accordance with theforegoing method was found to be an oil having a boiling point of about125 to 128 C. at 1 mm. pressure. Anal. calc. C, 42.71, H, 3.98, 01,28.02. Found: C, 42.85, H, 4.10, Cl, 27.72.

EXAMPLE 2 The text method employed has been. described by R. E. Heal ina paper entitled, Evaluating Protection of Fabrics from Clothes Moth andCarpet Beetle Attack (J. Econ. Ent, 35, 2) 249- 52 (1942).

-Woolen fabric was impregnated with acetone solutions of theinsecticides to give known concentrations on the fabric. fterevaporation of the solvent, 10 larvae of the black carpet beetle(Attagenus piceus (Oliv.)) were confined on weighed patches of thetreated fabric for two weeks. After removal of the larvae the patcheswere again weighed. The lossin weight of the 4 fabric is indicated asdamage in table below. Weight loss greater than 10 mg. is considered tobe inadequate protection.

The following table shows the results of the tests with the benzyl andtetrahydrofurfuryl esters of mucochloric acid esters:

Percent lowing additional tests were conducted in order to determine theefiicacy of the benzyl and tetrahydrofurfuryl esters in protecting woolfrom the ravages of the black carpet beetle and the webbing clothesmoth:

Black: carpet beetle test Damage to wool in mg.

Percent Applica- 1 ticn M ethyl ester Ethyl cstexzfl. Benzyl ester'lctrahydroi'uriuryl Damage greater than 10 mg. is considered inadequateprotection.

Webbing clothes moth test Percent Damage Applicato wool tion in mg.

Methyl ester 2 29. 4 Ethyl esten. 2 40. 6 Benzyl ester 2 G. 7

Damage greater than 10 mg. is considered inadequate QL'Ol'QCLlOD.

The above results indicate clearly the outstanding protection obtainedby the application of the benzyl and tetrahydrofurfuryl esters incomparison with the lower alkyl esters of mucochloric acid.

EXAMPLE 3 cockroach millcweed dug tests The test method employed followsa procedure of F. C. Nelson et al. as described in a paper entitledEvaluating Liquid Insecticides (Soap,

EXAMPLE 1 Stored grain insects The confused flour bee le (Tribol'iiimconfuswn (Duval)) was chosen as a typical pest of stored grains. Thebenzyl ester of mucochloric acid was found to be very effective incontrolling thisinsect. The test was made by dissolving the compound ina volatile solvent (e. g., 0014, CHCls, acetone, alcohol or the like)and impregnating a weighed sample of flour with the solution. Aftercomplete evaporation of the solvent the cake was ground and screened. Anequal number of control insects were placed on a starvation diet.Readings were taken at l, 7, 14 and 28 days. Final toxicity data werebased on values obtained when 50% of the control insects were dead fromstarvation. The data obtained in this manner served to distinguishbetween repellency and actual toxicity.

When the benzyl ester of mucochloric acid is tested in this manner at0.63% concentration, the kill was found to be 100%.

Various changes and modifications may be made in carrying out thepresent invention without departing from the spirit and scope thereof.Insofar as these changes and modifications are within the purview of theannexed claims, they are to be considered as part of my invention.

I claim:

1. An insecticidal composition containing as an active ingredient amucochloric acid ester selec- 2 ted from the group consisting of benzyland tetrahydrofurfuryl esters, and a carrier therefor.

2. An insecticidal composition containing as an active ingredient thebenzyl ester of mucochloric acid, and a carrier therefor.

3. An insecticidal composition containing as an active ingredient thetetrahydrofurfuryl ester of mucochloric acid, and a carrier therefor.

4. The method of killing insects which comprises contacting said insectswith a mucochloric acid ester selected from the group consisting of thebenzyl and tetrahydrofurfuryl esters.

5. The method of killing insects which comprises contacting said insectswith the benzyl ester of mucochloric acid.

6. The method of killing insects which comprises contacting said insectswith the tetrahydrofurfuryl ester of mucochloric acid.

HORACE D. BROWN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,226,183 Staud Dec. 24, 1940 2,362,565 Ladd Nov. 14, 19442,362,594 ter Horst Nov. 14, 1944 2,523,177 Yowell Sept. 19, 19502,532,579 Thomas Dec. 5, 1950 2,553,772 Kittleson May 22, 1951 2,553,778Hawley May 22, 1951

1. AN INSECTICIDAL COMPOSITION CONTAINING AS AN ACTIVE INGREDIENT AMUCOCHLORIC ACID ESTER SELECTED FROM THE GROUP CNSISTING OF BENZYL ANDTETRAHYDROFURFURYL ESTERS, AND A CARRIER THEREFOR.